Heavy equipment, such as load-haul-dump machines (LHDs), wheel loaders, carry dozers, etc., are used during an excavation process to scoop up loose material from a pile at a first location (e.g., within a mine tunnel), to haul the material to a second location (e.g., to a crusher), and to dump the material. A productivity of the excavation process can be affected by an efficiency of each machine during every excavation cycle. In particular, the efficiency of each machine increases when the machine's tool (e.g., a bucket) is fully loaded with material at the pile within a short amount of time, hauled via a direct path to the second location, and quickly dumped.
Some applications require operation of the heavy equipment under hazardous working conditions. In these applications, some or all of the machines can be remotely or autonomously controlled to complete the excavation process. When a machine is remotely or autonomously controlled, however, situational awareness may be limited. That is, it can be difficult for the remote operator or the automated system to accurately determine a degree of tool engagement with the pile during the loading segment of the excavation process. As a result, the machine's tool may be underloaded during a particular loading segment, or too much energy and time may be consumed by attempting to increase loading of the tool.
One attempt to improve efficiency in the loading segment of the excavation process is disclosed in U.S. Pat. No. 8,160,783 of Shull that issued on Apr. 17, 2012 (“the '783 patent”). Specifically, the '783 patent discloses a digging control system having a controller mounted on a wheel loader and in communication with a torque sensor, a pressure sensor, and a ground speed sensor. The controller calculates loading of the wheel loader's bucket based on signals from each of the sensors. The controller then compares the bucket loading to a threshold loading. When the bucket loading exceeds the threshold loading, the controller determines that the bucket has engaged a pile of material. Upon detection of pile engagement, the controller implements automated lifting and tilting of the bucket to fill the bucket with material from the pile.
Although the digging control system of the '783 patent may improve machine efficiencies somewhat, the system may still be less than optimal. In particular, the system may be able to determine only that the pile has been engaged to some extent, but not other parameters of the pile that can affect loading of the machine's bucket.
The disclosed excavation system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.